card speeds shows big differencesdepending onthe device used. So the values given by manufacturer web sites have insignificantvalue to decide. You must check reviews and independent test results of the specific device where the card will be used.A specific model ofcard mightwrite 10 M/s in a certain model camera, while same card might write 3 M/s in another model camera. The interface designs and electronics plays big role on access speed of the card.